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b6d7ee1f11
We still support *existing* channels. Just not new ones (before they could, in theory, explicitly ask for one). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
84 lines
2.7 KiB
C
84 lines
2.7 KiB
C
#include "config.h"
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#include <common/derive_basepoints.h>
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#include <common/key_derive.h>
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#include <common/keyset.h>
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bool derive_keyset(const struct pubkey *per_commitment_point,
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const struct basepoints *self,
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const struct basepoints *other,
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bool option_static_remotekey,
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struct keyset *keyset)
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{
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/* BOLT #3:
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*
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* ### `localpubkey`, `local_htlcpubkey`, `remote_htlcpubkey`, `local_delayedpubkey`, and `remote_delayedpubkey` Derivation
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*
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* These pubkeys are simply generated by addition from their base points:
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*
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* pubkey = basepoint + SHA256(per_commitment_point || basepoint) * G
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*
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* The `localpubkey` uses the local node's `payment_basepoint`;
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* The `remotepubkey` uses the remote node's `payment_basepoint`;
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* the `local_htlcpubkey` uses the local node's `htlc_basepoint`;
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* the `remote_htlcpubkey` uses the remote node's `htlc_basepoint`;
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* the `local_delayedpubkey` uses the local node's `delayed_payment_basepoint`;
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* and the `remote_delayedpubkey` uses the remote node's `delayed_payment_basepoint`.
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*/
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if (!derive_simple_key(&self->payment,
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per_commitment_point,
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&keyset->self_payment_key))
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return false;
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/* BOLT #3:
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*
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* ### `remotepubkey` Derivation
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*
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* The `remotepubkey` is simply the remote node's `payment_basepoint`.
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*/
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/* The old BOLT defined what happened prior to option_static_remotekey,
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* which we still support for existing channels:
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*
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* If `option_static_remotekey` or `option_anchors` is
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* negotiated, the `remotepubkey` is simply the remote node's
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* `payment_basepoint`, otherwise it is calculated as above using the
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* remote node's `payment_basepoint`.
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*/
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if (option_static_remotekey)
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keyset->other_payment_key = other->payment;
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else if (!derive_simple_key(&other->payment,
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per_commitment_point,
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&keyset->other_payment_key))
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return false;
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if (!derive_simple_key(&self->htlc,
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per_commitment_point,
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&keyset->self_htlc_key))
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return false;
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if (!derive_simple_key(&other->htlc,
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per_commitment_point,
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&keyset->other_htlc_key))
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return false;
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if (!derive_simple_key(&self->delayed_payment,
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per_commitment_point,
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&keyset->self_delayed_payment_key))
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return false;
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/* BOLT #3:
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*
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* ### `revocationpubkey` Derivation
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*
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* The `revocationpubkey` is a blinded key: when the local node wishes
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* to create a new commitment for the remote node, it uses its own
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* `revocation_basepoint` and the remote node's `per_commitment_point`
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* to derive a new `revocationpubkey` for the commitment.
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*/
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if (!derive_revocation_key(&other->revocation,
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per_commitment_point,
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&keyset->self_revocation_key))
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return false;
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return true;
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}
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